Speaking against animal foods although I am a reduced meat eater, animal foods tend to have a higher protein density, and therefore it is where the 10 % number comes from. (nutritionfacts.org)
Again, because of their low protein density they are not of much use in my view - you might as well eat my favorite food of all time which is black beans. (sweat4health.com)
If an insect needs to eat plants with a particular protein density but lives among a diverse group of crops, for example, then it will often get too little or too much protein and might have a harder time surviving. (psmag.com)